PSMA PET/CT and Multiparametric MRI in Assessing Local Extension and Lymph Node Metastasis in Prostate Cancer

This study aimed to evaluate the diagnostic performance of prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT), multiparametric magnetic resonance imaging (mpMRI), prostate-specific antigen (PSA), and maximum standardized uptake value (SUVmax) in detecting seminal vesicle invasion (SVI), extraprostatic extension (EPE), and lymph node (LN) metastasis in patients undergoing radical prostatectomy for prostate cancer (PCa).

A retrospective analysis was conducted on 66 patients who underwent preoperative PSMA PET/CT and radical prostatectomy between 2013 and 2024. mpMRI was available in 33 patients. Imaging findings were compared with histopathological results to assess the sensitivity, specificity, accuracy, and predictive values of PSMA PET/CT and mpMRI for detecting SVI, EPE, and LN metastasis. The relationships of PSA and SUVmax with pathological outcomes were also evaluated.

PSMA PET/CT demonstrated higher sensitivity and overall accuracy than mpMRI in detecting SVI, whereas mpMRI was more specific. For EPE detection, PSMA PET/CT was more sensitive, while mpMRI was more specific. Both modalities had similar predictive values. Although SUVmax and PSA showed a positive correlation, neither parameter significantly differentiated patients with or without SVI, EPE, or LN metastases. LN uptake on PSMA PET/CT was consistent with pathology in most cases, yet no significant association was found with SUVmax or PSA levels.

PSMA PET/CT is more successful in detecting SVI, whereas mpMRI is more prominent in EPE. The SUVmax value appears to be nearly significant in SVI and LN node metastasis. PSA has not shown a value for diagnosing local invasions of the prostate and LN metastases.